Revert "Mark async and generator functions as debuggable, so their frames are visible for return ty…

tests/language/async_or_generator_return_type_stacktrace_test.dart

Index: tests/language/async_or_generator_return_type_stacktrace_test.dart
diff --git a/tests/language/async_or_generator_return_type_stacktrace_test.dart b/tests/language/async_or_generator_return_type_stacktrace_test.dart
deleted file mode 100644
index 92883cc34ea7cb4c514a5260b5b6120133fbebd4..0000000000000000000000000000000000000000
--- a/tests/language/async_or_generator_return_type_stacktrace_test.dart
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import "package:expect/expect.dart";
-
-void badReturnTypeAsync() async {}  /// 01: static type warning
-void badReturnTypeAsyncStar() async* {}  /// 02: static type warning
-void badReturnTypeSyncStar() sync* {}  /// 03: static type warning
-
-main() {
-  try {
-    badReturnTypeAsync();  /// 01: continued
-  } catch(e, st) {
-    Expect.isTrue(e is TypeError, "wrong exception");
-    Expect.isTrue(st.toString().contains("badReturnTypeAsync"),
-                  "missing frame");
-  }
-
-  try {
-    badReturnTypeAsyncStar();  /// 02: continued
-  } catch(e, st) {
-    Expect.isTrue(e is TypeError, "wrong exception");
-    Expect.isTrue(st.toString().contains("badReturnTypeAsyncStar"),
-                  "missing frame");
-  }
-
-  try {
-    badReturnTypeSyncStar();  /// 03: continued
-  } catch(e, st) {
-    Expect.isTrue(e is TypeError, "wrong exception");
-    Expect.isTrue(st.toString().contains("badReturnTypeSyncStar"),
-                  "missing frame");
-  }
-}